Assessing the Economic Viability of the Mechanized Removal of Understory Beech during a Shelterwood Harvest

Beech bark disease is a pathogenic complex that has been spreading throughout the American beech’s range since the 1800s. A litany of negative consequences have manifested from the infestation of this disease, many of which deteriorate the ecological functions of forestland. This case study sought to analyze the cost structure for removing a recalcitrant beech understory via mechanized shelterwood harvesting. High-resolution data regarding the day-to-day operation of harvesting equipment was collected using daily production journals. Interviews were conducted with the logging company owner and maintenance supervisor to gather additional information required to calculate machine costs, overhead, job specific costs, and trucking costs. The yield from this harvest was 527 metric tonnes of sawtimber and 4,893 tonnes of clean chips. The total harvesting cost equated to $4,651/ha, with the cost attributed to removing beech at $204/ha. Despite the additional cost of beech removal, the logger generated a total profit of $5,965 and a return on investment of 7.5%, allowing us to conclude that mechanized harvesting can be a viable beech removal strategy given the forest stocking and market conditions that are in place. Study Implications This study breaks down the various costs associated with cutting, skidding, landing, and transporting wood products from a mechanized harvesting operation designed to remediate the effects of beech bark disease. The beech remediation harvest was economically viable for both the landowner and the logger because the timber sale included some valuable hardwood sawtimber, and the harvest system was capable of generating clean chips for a pulp mill with the low-grade hardwood. Furthermore, the landowner’s willingness to accept lower sawtimber stumpage revenues allowed the logger to make a profit and return-on-investment on the job. Had the timber sale been limited to only hardwood pulpwood or fuel chips, the operation would not have been economically viable without the landowner paying for the operation, which, based on our analysis, would be approximately $200/ha.

A review on future wastewater treatment technologies: micro-nanobubbles, hybrid electro-Fenton processes, photocatalytic fuel cells, and microbial fuel cell

The future prospect in wastewater treatment technologies mostly emphasizes processing efficiency and the economic benefits. Undeniably, the use of advanced oxidation processes (AOPs) in physical and chemical treatments has played a vital role in helping the technologies to remove the organic pollutants efficiently and reduce the energy consumption or even harvesting the electrons movements in the oxidation process to produce electrical energy. In the present paper, we reviewed several types of wastewater treatment technologies, namely micro-nanobubbles, hybrid electro-Fenton processes, photocatalytic fuel cells, and microbial fuel cell. The aims are to explore the interaction of hydroxyl radicals with pollutants using these wastewater technologies, including their removal efficiencies, optimal conditions, reactor setup, and energy generation. Despite these technologies recorded high removal efficiency of organic pollutants, the selection of the technologies is dependent on the characteristic of the wastewater and the daily production volume. Hence the review paper also provides comparisons between technologies as the guidance in technology selection.

An ESP Production Optimization Algorithm Applied to Unconventional Wells

The objectives and Scope is to evaluate the feasibility of a Production Maximization algorithm for ESPs on unconventional wells using projected operating conditions instead of current ones, which authors expect will be crucial in adjusting the well deliverability to optimum frequencies on the rapidly changing conditions of tight oil wells. Actual production data for an unconventional well was used, covering from the start of Natural Flow production up to 120 days afterwards. Simulating what the production would be if a VFD running on IMP Optimization algorithms had been installed, new values for well flowing pressures were calculated, daily production scenarios were evaluated, and recommended operating frequencies were plotted. Result, observations, and conclusions: A. Using the Intelligent Maximum Production (IMP) algorithm allows maximum production from tight oil wells during the initial high production stage, and the prevention of gas-locking at later stages when gas production increases. B. The adjustment of frequency at later stages for GOR wells is key to maintaining maximum production while controlling free gas at the intake when compared against controlling the surface choke. Novel/additive information: The use of Electrical Submersible Pumps for the production of unconventional wells paired with the use of a VFD and properly designed control algorithms allows faster recovery of investment by pumping maximum allowable daily rates while constraining detrimental conditions such as free gas at the intake.

An Integrated and Automated Workflow to Enhance Production Efficiency and Compliance in a Giant Offshore Field

Daily production compliance is fundamental to sustain reservoir management excellence and ultimately achieve an optimum oil recovery. The production activities execution is critical to adhere to the reservoir management guidelines and best practices. It is a more challenging task in brownfields due to the limitation of controlling system and limited access especially in offshore fields. A timely and efficient approach is undoubtedly necessary to enhance production efficiency and compliance. An integrated and automated tool has been innovated to analyze and report well production status against the guidelines and requirements in a mature offshore field with more than 50 years history. This systematic approach has been developed through integrating the planned rate, daily actual production rate, latest flow tests, and current well performance. Noncompliance is reported automatically on a user defined time scale, including daily, weekly, monthly or any customized time range within the month time. Daily violation report is generated automatically and sent to production operation for prompt adjustments and other requested actions. The automated workflow enables both daily production reporting and production compliance reporting. Daily production reporting is a routine work, which usually takes a lot of time every day. The workflow is capable of reducing 90% of the time comparing to the manual way. Production compliance reporting is currently mainly focusing on the comparison of actual production to planned rate and guideline rate. Any exception will be reported as violation. The violation dashboard summarizes the details based on the user selected time range. On daily basis, an email containing the violation details could be generated and sent to the corresponding teams for corrective actions. In this giant brown field, production GOR is a primary controlling parameter. The latest flow tests have been taken into account to evaluate the gas production compliance. Any violation to the GOR guidelines will be reported in the same communication email for timely correction. With the innovated tool, the violation ratio of the giant offshore field has been successfully reduced and controlled. The usual responding time for corrections has been dramatically reduced from months to days.

Development Wells Optimum Management Technique Coping with Production Curtailment for Stacked Oilfields Consisting of Multiple Complex Reservoirs

Affected by the Covid-19 pandemic and low oil prices, OPEC members were forced to curtail production. The H oilfield in Iraq commenced production curtailment in early March 2020 and then oil production gradually decreased. By the end of 2020, production was less than one-third of the rate before curtailment. There are multiple sets of oil-bearing formations in the H Oilfield vertically. The developed oil reservoirs have a total of more than three hundreds development wells. The reservoir types are diverse, the relationship among multiphase fluids is complex, and the development methods are different. The reduction of the daily production will inevitably require a comprehensive strategy adjustment to cope with the new situation. Any intentional or unintentional shut-in has a price. Therefore, the key is how to reasonably control the production in many oil reservoirs and re-adjust the oil reservoir development plan at the minimum cost while meeting the overall changing production restriction target for each oil reservoir. In this study, the author established a simple and fast process for judging open and closed wells through years of experience in reservoir dynamic analysis and field management. Step 1: Wells are classified according to production characteristics. For pre-selected wells, some wells with unique functions that need to be opened and those that need to be closed for objective reasons should be excluded. Step 2: Conduct single well cost analysis with reference to production status. Respectively evaluate the performance of the production well under the state of opening and closing. Step 3: Establish the model with economic indicators as the objective function. According to different goals, the model established is slightly different. Step 4: Optimize the best solution based on actual needs. Solve the optimal solution under the target and optimize the number of reasonably configured wells in each reservoir. Through this process, combined with historical and current actual production conditions, different types of oil wells in all reservoirs are classified. Their priorities of reopening are evaluated to meet the needs of other production restriction targets and ensure the smooth transition of oilfield development.

Caractérisation des déchets solides ménagers de Faladié

Cet article est une étude expérimentale pour de connaitre la caractérisation et la quantification des déchets solides ménagers du quartier de Faladié dans la commune VI du District de Bamako. A Faladié, comme dans la plupart des communes de Bamako avec comme problématiques environnementales majeures, une insalubrité alarmante, qui accentue en partie les maladies comme : le paludisme, la fièvre typhoïde, le choléra, les infections respiratoires, les anémies, .... C’est dans ce contexte que la présente étude, voulant résorber l’épineuse problématique qu’est la gestion des ordures ménagères, a été coordonnée pour connaitre « la caractérisation des déchets ménagers au niveau des dépôts intermédiaires et finaux d’une part ; et de contribuer à la mise en place d’un système de tri adapté à Faladié d’autre part ». L’approche méthodologique d’échantillonnage utilisée pour déterminer la taille d’échantillon de déchets à trier est définie par la production journalière d’ordures ménagères d’un échantillon de la population totale par catégorie en satisfaisant à un niveau de confiance de 95 %. Ainsi, le tri manuel a porté sur le contenu de deux (2) bennes de 7m³, un total de 14m³ d’ordures ménagères, soit 7382,7 kg. Dans ces conditions, l’étude a permis de dégager la caractérisation des ordures ménagères et de différencier les types de déchets valorisables de Faladié. En outre, nous avons déterminé qu’il est généré chaque jour 0,27 kg par habitant (soit 0,27 kg/habitant/jour). A la suite de l’étude, des propositions stratégiques ont été formulées à la Mairie de la Commune VI dans le sens de mettre en place un comité de gestion intégrée des déchets. This article is an experimental study for the characterization and quantification of solid household waste in the Faladie neighborhood in the commune VI of the District of Bamako. In Faladie, as in most of the communes of Bamako with major environmental problems, an alarming insalubrity, which accentuates in part diseases such as: malaria, typhoid fever, cholera, respiratory infections, anaemia, It is in this context that the present study, aiming to solve the thorny problem of household waste management, was coordinated to find out « the characterization of household waste at the level of intermediate and final depots on the one hand; and to contribute to the setting up of an adapted sorting system in Faladie on the other hand». The methodological sampling approach used to determine the sample size of waste to be sorted is defined by the daily production of household waste of a sample of the total population by category at a 95% confidence level. Thus, the manual sorting involved the contents of two (2) 7m³ skips, a total of 14m³ of household waste, or 7382.7 kilograms. Under these conditions, the study allowed us to characterize the household waste and to differentiate between the types of recoverable waste in Faladie. In addition, we also determined that 0.27 kilogram per inhabitant is generated every day (i.e. 0.27 kilogram/inhabitant/day). Following the study, strategic proposals were formulated to the Commune VI Town Hall to set up an integrated waste management committee.

A Novel Data-Driven Model for Dynamic Prediction and Optimization of Profile Control in Multilayer Reservoirs

Establishing reservoir numerical simulation and profile control optimization methods considering the mechanism of profile control has always been a difficult research problem at home and abroad. In this paper, firstly, a physics-based data-driven model was established on daily production data of injection and production wells following the principle of material balance. Key parameters including transmissibility, control pore volume, water injection allocation factors, and injection efficiency are derived directly from history matched model, and the dominated flow channels could be quantitatively identified. Then, combined with the evaluation results of the plugging ability of the plugging agent, imaginary well nodes are added to the existing interwell relationship to characterize the heterogeneity of interwell-specific parameters. This process performs flow processing along the interwell control units, forming a new and rapid method for simulation and prediction. Lastly, based on the calculated interwell transmissibility, water injection efficiency, and allocation factors, injection wells with low water injection efficiency can be preferentially selected as profile control wells. In addition, taking the production rates, injection rates, and the amount of plugging agent as optimization variables, we established an optimal control mathematical model and realized the parameter optimization method of the profile control. We demonstrated the results of one conceptual model and two indoor experiments to verify the feasibility of the proposed method and completed two actual field applications. Model validation and actual field application show that the proposed method successfully eliminates the complicated geological modeling procedure and the tedious calculation process associated with the profile control treatment in traditional numerical simulation methods. The calculation speed improves tens or hundreds of times, and water channeling paths are accurately identified. Most importantly, this method realizes the overall decision-making of profile control well selection, dynamic production prediction, and parameter optimization of profile control measures quickly and accurately by mainly using the daily production data of wells. The findings of this study can help for better understanding of the optimization design and application of on-site profile control schemes in large-scale oilfields.

Implementation of participatory pre-collection in the sustainable management of household solid waste: case of the district of Douala V in Cameroon

EPI sciences The main objective of this study in the district of Douala V is to set up participatory pre-collection of household solid waste which, by protecting the environment, promotes the recovery of this waste. More specifically, the aim was to make an inventory of solid waste management, to raise awareness of households on participatory pre-collection, to describe the technical organization of the service and to evaluate the parameters of financial analysis for a pre-collection activity. To do this, available documents, direct observations, interviews and survey form were used. The main results of this study showed that the daily production or ratio of one inhabitant of Douala V is 1.05kg/hab/jour; the annual production is estimated at 363,870 tons. The low collection rate of about 23% was observed. With regard to household sensitization, 43% of the households surveyed are willing to pay for the pre-collection service and 52% are against and 5% are uninformed. The provisional financial analysis is based on one year; the investment cost is estimated at 3 327 400 CFA (5079 €). Overall, it appears that the solid waste collection rate in Douala V is below average, so it appears that pre-collection and recovery of household solid waste have a major role to play in the solid waste management system. Cette étude déroulée dans l’arrondissement de Douala V a pour objectif principal de mettre sur pied la pré-collecte participative des déchets solides ménagers qui en protégeant l’environnement, favorise une valorisation de ces déchets. Il s’agissait plus spécifiquement de faire un état de lieux de la gestion des déchets solides, de sensibiliser les ménages sur la pré-collecte participative, décrire l’organisation technique du service et d’évaluer les paramètres d’analyse financière pour une activité de pré-collecte. Pour ce faire, des documents disponibles, observations directes, entretiens et fiche d’enquête ont été utilisés. Les principaux résultats de cette étude ont montré que la production journalière ou ratio d’un habitant de Douala V est de 1,05kg, la production annuelle est estimée à 363 870,45 tonnes. Le taux de collecte faible d’environ 23%. Pour ce qui est de la sensibilisation des ménages, 42,66% des ménages enquêtés sont prêts à payer pour le service de pré-collecte et 52,33% sont contre et 5% sont sans avis. L’analyse financière prévisionnelle est basée sur une année, le coût d’investissement s’estime à deux mille huit cent quatre-vingt-onze Euro (2 891 Euro). Il ressort globalement que le taux de collecte des déchets solides à Douala V est en dessous de la moyenne, il apparait donc que la pré-collecte et la valorisation des déchets solides ménagers ont un rôle majeur à jouer dans le système de gestion des déchets solides.

Investigation of Energy Recovery from Municipal Solid Waste: A Case Study of Al-Karak City / Jordan

Municipal solid waste (MSW) from Al-Karak city is monitored and characterized. The MSW is sorted into 14 different waste categories. In addition, the MSW is separated into several size fractions, followed by sorting and characterization. The average daily production rate of waste is 61.5 ton/day. The MSW generated per capita is estimated to be 0.55 kg/capita/day. The main input MSW comprised a modest proportion of organic content 38.8 %. Other combustible fractions are present in significant proportions, allowing the waste to be utilized for energy recovery. Refuse-derived fuels (RDFs) may be made from waste fractions > 100 mm and 50 – 100 mm.